IBS is a diagnosis of last resort. You don't get that from a walk-in clinic, you get that from a months- or years-long quest to eliminate every possible cause, before your doctor throws up their hands and calls it IBS.
Yeah, true. Different doctors have different standards, and there are significant regional differences in standards of care. I've had several walk-in clinics tell me that I need an established GP to deal with certain issues.
If you've been suffering acute IBS for months and can't get a regular doctor's appointment in that time, why would that not be considered a case for urgent care?
This whole store lacks enough detail to know exactly what's going on, however, so we're all going to project our biases on it. If you're anti-Amazon you're going to project your assumptions of unfair business practices. If you're skeptical of that position you're going to project your skepticism into the unknowns of the story. Really there aren't enough facts here to know if this is Amazon firing an underperforming employee who is lying about a health condition, or failing to accommodate an employee with a legitimate health problem.